Recent advances and future outlook in mode-locked lasers with multimode fibers

Abstract

Multimode fibers (MMFs) have attracted interest because of their larger mode area and additional spatial degrees of freedom compared with single-mode fibers. Recently, MMFs have been introduced into mode-locked lasers for new cavity structures with better laser performance. Among these lasers, there are two remarkable cases in which MMFs are the key components for mode-locking: One is using a short segment of the MMF as a saturable absorber (SA), which has the advantages of high damage threshold, wide operating bandwidth, and low cost. The other is the construction of multimode cavities with MMFs. Spatiotemporal mode-locking (STML), a general form of mode-locking, can be achieved in such cavities. Herein, we review these two types of mode-locked lasers with MMFs. The principles of MMF-based SA and STML are described based on the common theory of multimode nonlinear fiber optics. Subsequently, we present a detailed overview of the recent progress regarding these lasers, including lasers mode-locked by MMF-based SAs at the 1-, 1.5-, and 2-μm bands, as well as spatiotemporal mode-locked MMF lasers. A perspective for the development of mode-locked lasers with MMFs is also provided.

Extra-cavity modulation of a chirped Gaussian bisoliton

“…Of course, scalar solitons can be generated using an all-polarization-maintained fiber laser cavity. Besides, multi-mode fiber is introduced in previous reports, to investigate the spatiotemporal optical soliton [11][12][13]. In this situation, the output single-pulse energy will be improved, accompanied with a lower laser beam quality factor (M 2 ).…”

Coherent mode locking in a two-section laser with fast gain and absorber

“…The generation of ultrashort pulses remains an important part in modern physics [1][2][3][4][5][6][7][8][9][10] due to the huge number of potential applications such as atomic clock measurements [11], astrophysics [12], distance metrology [13], frequency comb spectroscopy [14] and others [15][16][17]. Naturally it is rather complicated to create compact sources of THz and mid-IR (MIR) ultrashort pulses for systems of non-stationary spectroscopy [18], frequency metrology [19], time domain spectroscopy [20], nondestructive testing [21], etc.…”

Tutorial: How to build and control an all-fiber wavefront modulator using mechanical perturbations

“…In the past several decades, there has been an ongoing effort to utilize multimode optical fibers (MMFs) in photonic applications such as space-division multiplexing for optical fiber communication [1][2][3][4], nonlinear optics [5][6][7][8][9][10][11][12] and imaging [13][14][15][16][17][18][19][20][21]. More recently, applications for MMFs have expanded to quantum optics [22][23][24][25][26] and fiber lasers [27][28][29][30][31]. These numerous applications enjoy the ability of MMFs to transport many spatial modes with low loss, while having a low cost and a small footprint.…”